Now a team
at the University of Bengal in India, led by Dhruba Dasgupta, has
become the latest to cause a stir, reporting that they have observed
what possibly appears to be superconductivity at 313 K.

The
researchers used lead zirconium titanate (PZT) -- a common material
used in capacitors and other electronics -- for the work. They
first cut a 2 cm × 2 mm piece of a commercial disks of the
material. They then stripped away the existing silver coating
and coated the piece with 4000 Angstroms of aluminum via vacuum
evaporation.

The conductivity was then probed along the
sample. The place where the conductivity sharply increased
beneath 313 K appeared right at the interface of the PZT and its
aluminum coat.

It
is important not to jump too swiftly to conclusions. The
measurements of conductivity could have been flawed, or they may not
represent "true" superconductivity. The paper has not
yet been peer reviewed or published in a journal. Given its
impressive claims, and reportedly elementary process to achieve them,
it will likely soon see peer review.

The idea of such a simple
metal mix acting as what is essentially the holy grail of
electronics, certainly sounds too good to be true.

However, if
it does prove to truly be room temperature superconductivity, the
discovery would revolutionize a number of industries including
computing and power transmission. One can only hope that this
discovery -- or one in the near future -- is validated, so we can at
last reap the benefits
of superconductors without special equipment.

Some of
the recent research into superconductors has focused on determining
how they work, in an effort to come up with new designs. To
read more about this, check out our
January 2008 andJuly
2008 pieces on this topic.

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It doesn't seem like what they did would great a superconductor at all. Coating material X with 400 nm of material Y isn't how you make a superconductor. If you measured the conductivity of such a sample, you are just measuring the conductivity of Material Y. No new material was created, unless there was some annealing step that this article forgot to mention. This seems doubtful at best.

Firstly, the band structures of the metals have no bearing on the superconductivity of a material. Superconductivity is due to the interaction between electrons and phonons (lattice vibrations). An electron traveling through a superconductor will interact with the lattice and the corresponding phonon will link another electron to the first. The pairing of the two electrons (which are fermions), will create a boson. Bosons behave very differently than fermions, and the band structure of a given material becomes completely irrelevant at this point.

Secondly, a 4 point probe measurement of the sample involves contacting the SURFACE in 4 places. If the surface is aluminum or silver, then it would seem likely that is where the current will flow through as the field lines will be between the probes, not across the interface.

Finally, I agree that if there is zero resistance, it's a superconductor. I was merely expressing my doubt that the measurement was correct on the basis that their "superconductor" material is outside the regular definition. But, I'd love to be proven wrong! Bring on the superconducting revolution!

Your link... to hyperphysics (what a great place to become an expert on physics..) discusses the energy gap (not the band structure) for cooper pairs. This is essentially the energy required to break up the pair. Thus the energy of phonons in the system cannot be greater than this value to maintain superconductivity. That is hardly a band structure in terms of the regular solid state physics definition.

Also, discussing BCS superconductivity is irrelevant. Type I superconductors (pure elemental materials) that follow BCS theory cannot be superconducting at room temperature. It is not possible due to the same energy gap that you reference. Type II superconductors (Cuprates) MIGHT one day be superconductive at room temperature, but to date it hasn't been achieved. The underlying mechanism for superconductivity in Type II superconductors is still debated, but it is not the same simple BCS theory. What is described in this article is certainly not a Type II (cuprate), which is what I was getting at in my last post. Unless all of those incredibly smart solid state physicists since the 80s completely forgot about PZT, I doubt this is anything but a hoax. The addition of pure aluminum makes this even more suspect since aluminum has one of the lower critical temperatures.

"If you look at the last five years, if you look at what major innovations have occurred in computing technology, every single one of them came from AMD. Not a single innovation came from Intel." -- AMD CEO Hector Ruiz in 2007